An initial disclosure of TAA's was made in an application for two Damon Runyon grants in 1962, and resulted in a grant award on Jan. 1, 1963 as Damon Runyon Grants 722 and 723 to the applicant as principal investigator through the Office of Sponsored Research, The George Washington University. This early work was performed in animal models, first using cancer cells in tissue culture and their growth in a privileged immunological site in Syrian hamster cheek pouches. The identification of membrane components separated from the rest of the cell and their effect in reducing the size and the number of tumors was the first report of its kind in the worldwide literature. There followed a group of studies, first on randombred hamsters with transplantable adenovirus type 12-induced tumors in which the separated, identified, soluble tumor-specific transplantation antigens derived from the soluble materials of separated tumor cell membranes showed a strong, titration-dilution curve effect in blocking tumor growth. This work was presented first at an international conference in 1967, followed by a series of published papers, first on randombred and later repeated by another institution, in cooperation with the inventor, in inbred hamsters. These studies with virus-induced tumors were then repeated by yet another institution, in cooperation with the applicant, using carcinogen-induced tumors in inbred mice. Concomitant research began in 1965 through 1968 on laboratory separation and identification studies of human cell membrane components in specific developing embryonic and fetal tissue cells, adult normal tissue cells and benign disease adult tissue cells of humans so as to further understand the distribution of normal cell membrane components, tissue antigens. The methods used in the initial work on the human HeLa cell-hamster cheek pouch model, the adenovirus-tumor hamster model and the carcinogen-induced mouse model were further perfected and established as the basis for these studies of human non-malignant tissues. These studies were then followed by studies of the cell membrane components of tumors of the same, counterpart organ. Tumor-associated antigens were separated, characterized and tested for characteristic activity and recorded as quantitatively or qualitatively unique. One such study was reported for colon cancer TAA at a 1968 Gordon Conference, with subsequent publication of these observations in Lancet in 1970, with appropriate standards and controls. Controls consisted of 1st, 2nd and 3rd trimester fetal, and adult normal and benign cell membrane soluble, separated proteins as well as TAA produced by different human tumors, thus permitting cross-reaction and comparison studies of organ-related tumor associations.
A major initial criterion involved controlled clinical evaluations of the ability of TAA to induce both allogeneic and autologous delayed hypersensitivity reactions in appropriate, related-for-cancer-type nonanergic cancer patients with primary tumors, both pre- and post-surgery. This major criterion continued to be the basis for a series of studies of different selected human cancer TAAs, along with other appropriate assays and techniques suitable for a general application or for a particular TAA, with newer methods continually assessed for application. These studies permitted evaluations of hundreds of individual fresh tissues and tumors, and allowed in vitro and in vivo comparisons and the development of preliminary clinical studies and clinical protocols for evaluation of appropriate immunogenic activities of purified TAAs.
In 1976 early results from a lumg cancer immunotherapy study were reported to the New York Academy of Science, suggesting the possibility that TAAs might be capable of producing effective, long-lasting cell-mediated immunity in the human host. There followed other clinical studies of candidate TAAs for other forms of cancer. Statistical proof of the existence of TAAs which produce cell-mediated immune reactions which are effective in the host could not be established until phase I studies for safety and phase II and III studies for efficacy were completed. In late 1986, such proof became available for lung cancer TAAs, and it is now possible to claim the existence of TAAs that produce cell-mediated immune reactions which are effective in the treatment of human cancer, thus verifying the methods and approaches used for the production of pure TAA and ultrapure TAA and epitopes therefrom. In 1980, the development of TAA monoclonal antibodies began, with a view to further understanding the TAAs. These ongoing studies, so far, have indicated the superiority of a further development, namely, the monoclonal antibody-derived epitopes of TAA selected among active antigenic determinants. Research results thus far indicate that enzyme immunoassays measuring antibodies in patient sera to TAA or to TAA monoclonal antibody-derived epitopes display superior superficity and greater utility than enzyme immunoassays using TAA monoclonal antibodies to monitor patient sera. The entirety of the sequence of methods thus far utilized for preparing TAA epitopes with these properties are described herein. References above to the work of applicant are not intended as an admission that such work constitutes prior art under U.S. law.
It is important to the art that tumor associated antigens be isolated in a pure but also active form, which degree of purity is referred to herein as "pure" for use in immunotherapy, and "ultrapure" for use in characterization, identification and for epitope preparation. Pure TAA's are obviously superior to less pure TAA's where utilized for their ability to produce cell-mediated immune reactions to the TAA. A particular use of ultrapure TAA that has been utilized by the applicant is in the production of hybridoma cell lines to obtain monoclonal antibodies for use in preparing tumor-associated antigen epitopes, which are useful as monitors of specific active immunotherapy, for measuring specific antibody responses in patients undergoing immunotherapy.